The present invention relates to fluid dispensing pumps generally, and more particularly to mechanical fluid dispensing pumps, and especially mechanical gasoline pumps, having mechanical display wheels to record their transaction price and which are limited in their unit volume price settings.
Most gasoline pumps in place throughout the United States and Canada are mechanical and are limited to a unit volume price setting of 99.9.cent. per gallon, a unit volume price which in 1979 is quickly being exceeded. Once the price of gasoline exceeds the $99.9.cent. per gallon figure, the station operator owning a conventional mechanical pump must set the pump's price setting to a per gallon figure which is some fractional value of the desired full per gallon price. It has become commonplace, for example, to quote gasoline prices in terms of a half gallon price. With this setting the operator multiplies the dollar amount appearing on the pumps mechanical transaction display by two (2) to determine the actual price of the transaction. The drawback to this practice is that it leads to confusion and error because of the need to make a mental conversion from the pump's displayed transaction price, which is tied to the pump's unit volume setting, to the actual transaction price. The practice has been criticized, however, the solution involves a major overhaul or replacement of the old pump which is expensive and economically prohibitive for many station owners. The need for fractional pricing could be eliminated for the present if the stations switched to liters, however, there is substantial resistance to such a change-over because of the familiarity with the English system of measure.
The present invention provides a relatively inexpensive solution to the limited display range problem of existing mechanical pumps by providing an electronic price conversion and display system which can be retrofitted to existing pumps without need for pump replacement or expensive pump modifications. The invention is adapted for easy installation on existing pumps and automatically takes the total transaction price mechanically displayed on the existing mechanical pump, multiplies it by a selected factor, such as two or three, and displays the result as a digital readout easily viewable by the pump operator and customer. The invention permits the pump operator to reduce his unit volume price setting on the pump to a fractional value of the actual unit volume price and have a total and accurate transaction price digitally displayed at the pump.